September 12, 2013

Recordings Of Predator Sounds May Help Keep Raiding Elephants At Bay

When confronted with the sound of leopard growls, wild elephants will actually trumpet and growl back. But, when they hear the sound of a growling tiger, they slink away quietly, according to a research team from the University of California, Davis. Their findings, published in Biology Letters, might help Indian farmers protect their crops from marauding elephants and potentially save the lives of both people and animals.

"We noticed that the elephants were more scared of tigers than of leopards," said Vivek Thuppil, who carried out the work as part of his Ph.D. in animal behavior. Thuppil collaborated with Richard Coss, professor of psychology at UC Davis.

In an effort to prevent future conflicts between human farmers and elephant herds raiding the fields at night, the research team conducted the first elephant behavior study focused on nighttime antipredator behavior.

In India, elephants raiding crops is a serious problem. Drums, firecrackers and electrified fences are all defenses that farmers use to keep elephants from their crops. During these encounters, an average of 400 people a year are killed. Approximately 100 elephants are killed through poisoning, electrocution or other means, according to an Indian government report.

For the study, the researchers set up infrared beams that would initiate playback of leopard or tiger growls and capture of the event on video when elephants crossed paths leading to crop fields.

Tigers will sometimes attack a young elephant that becomes separated from the herd, however, leopards are not known to prey on elephants.

The elephants displayed very different initial reactions to both big cat growls, but ultimately retreated from both noises.

Thuppil said the elephants might be confused by the leopard growl, as a real leopard would most likely retreat from an elephant herd. The researchers say there is no benefit for elephants to risk an encounter with a leopard, even if it isn't a known predator.

"You don't want to mess with something with claws and teeth," Thuppil said.

"They're acting in a very intelligent way," Coss said.

In the forest areas of India, wild elephant populations are stable and possibly increasing. The forest areas are protected, however, human settlement has increasingly moved into the buffer zone surrounding the forest. Elephants pass through these buffer zones while foraging or visiting different patches of forest.